Tobacco smoke filters have been produced that incorporate a flavor agent where the agent is applied uniformly over the filtering material before the filtering material is gathered and shaped to form the filter product. An example of these conventional filters includes a flavored tobacco smoke filter made from bonded cellulose acetate filamentary tow in which a liquid plasticizer such as triacetin is sprayed uniformly over the tow before it is gathered to its final rod form. The flavoring agent is normally dissolved in the liquid plasticizer, and the plasticizer effects the bonding between adjacent filaments.
Other methods of producing cigarette filters are disclosed in U.S. Pat. Nos. 4,549,875, 4,768,526 and 4,281,671.
It has been found in practicing the conventional methods for producing tobacco smoke filters that problems result when the use of a particular flavoring agent is to be terminated or when one flavoring agent is to be substituted for another. These problems result because the spray booth within which the plasticizer is applied will be contaminated with the first flavoring agent employed, so that the subsequently produced filters would be contaminated unless production was stopped and the contaminated booth was cleaned or replaced.
Known methods for introducing a flavored element into the interior of a filter have also suffered from the disadvantage that flavorant is often not introduced in the proper amounts or at the proper location within the cigarette filter to achieve the desired effect on the smoke passing through the filter, and the position of the flavored element within the smoke filter could not be precisely controlled.